28782157 has 4 divisors (see below), whose sum is σ = 28848160. Its totient is φ = 28716156.

The previous prime is 28782133. The next prime is 28782197. The reversal of 28782157 is 75128782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 75128782 = 2 ⋅37564391.

It is a cyclic number.

It is not a de Polignac number, because 28782157 - 2¹¹ = 28780109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28782197) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32343 + ... + 33220.

It is an arithmetic number, because the mean of its divisors is an integer number (7212040).

Almost surely, 2^28782157 is an apocalyptic number.

It is an amenable number.

28782157 is a deficient number, since it is larger than the sum of its proper divisors (66003).

28782157 is an equidigital number, since it uses as much as digits as its factorization.

28782157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66002.

The product of its digits is 62720, while the sum is 40.

The square root of 28782157 is about 5364.9004650599. The cubic root of 28782157 is about 306.4604577541.

The spelling of 28782157 in words is "twenty-eight million, seven hundred eighty-two thousand, one hundred fifty-seven".